IEEE 1206-1994

This standard covers handsets and headsets whose receive performance can be measured using standardized artificial ears, as defined in ITUT Recommendation P.57: 1993 and ANSI S3.36-1985. The standard also covers handsets and headsets whose transmit performance can be measured with the center of the transmitter sound port in front of the artificial mouth lip plane. Othere types of handsets or headsets, having transmitters whose sound ports fall behind the lip plane in normal use, are not covered by this standard. However, the general methods described in this standard may be used as guidelines for testing such handsets or headsets. This standard covers measurements on four-wire handsets and headsets having separate transmit and receive speech paths. This standard also applies to three-wire handsets and headsets in which a common lead is shared between the transmit and receive circuitry. When handsets and headsets are connected to hybrid speech networks performing four-wire to two-wire conversion, their transmission performance may be measured using the methods of IEEE Std 269-1992, with due consideration given to the relevant transmitter positioning and receiver coupling issues discussed in this standard.

This standard describes practical methods for measuring the transmission characteristics of a telephone handset or headset by means of using a test connection to obtain objective measurements. Although the various methods generally produce similar results, some deviations can be expected depending on handset or headset characteristics. Measurement conditions should be noted when reporting results. The obtained test results may be used as a means of evaluating or specifying the transmission performance of a handset or headset on a standardized basis. This standard is intended for measuring the transmission performance over the frequency range most useful for speech, 100-5000 Hz. It is to be used for both single-frequency and varying-frequency measurements (such as continuous slow sweeps or equivalent, e.g., closely-spaced discrete steps). Continuous spectrum signals with one- or two-channel spectrum analysis methods, to the extent that they are equivalent to or better than the methods described herein, may also be used. These two types of signals (sinusoidal and continuous spectrum) give essentially identical results for devices measured in the linear region of their operation, when the measurement is sufficiently noise-free. For nonlinear devices, however, the continuous spectrum is preferable. Nonlinear devices include carbon microphones, compressors, automatic gain control (AGC) circuits, etc. For guidance in using continuous spectrum signals, see IEEE Std 269-1992 . Drawings and test procedures, as well as other pertinent information, are included as an aid for use in setting up the tests. The basic accuracy and reproducibility of measurements taken in accordance with this standard depend primarily upon the accuracy of the test equipment used, the care with which the calibration and measurements are conducted, and the inherent stability of the handset or headset under test. Where a given set of measurements is repeated in the same laboratory and by the same operator, a relatively high degree of reproducibility normally should be obtained. However, when comparing measurements taken by different laboratories, allowances should be made for the influencing factors mentioned above.

New IEEE Standard - Superseded. Practical methods for measuring the transmission characteristics of telephone handset or headset by means of using a test connection to obtain objective measurements are provided. The obtained test results may be used as a means of evaluating or specifying the transmission performance of a handset or headset on a standardized basis.